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Tests Evaluating Crabwalk Moves

Mars Exploration Rover team members prepare a testing setup for a subsequent experiment after an experiment driving the rover in a crablike motion, with all four corner wheels angled to the right.› Full image and caption

On firm ground, NASA's Mars Exploration Rovers can make crablike moves by turning all four steerable wheels to the same side angle, then rotating the wheels either forward or backward. The rover team is experimenting with variations of those maneuvers in a test sandbox at JPL as part of its work to identify the best way to get Spirit out of the loose soil where the rover has become embedded on Mars.

By Friday morning, July 10, the team had tested crabwalk patterns driving forward in the test sandbox with the wheels turned at 60 degrees to the right and 20 degrees to the right. The angle of motion was upslope in the testing setup that simulates Spirit's predicament on Mars. Together with earlier experiments evaluating straight-forward and straight-backward driving, the latest actions completed four out of 11 maneuvers that the team has on its current testing list. Next, engineers plan to test backward (downslope) crabbing with wheels turned 60 degrees to the right.